Method of repairing a manhole chimney using a stretchable sleeve

ABSTRACT

A method of repairing and renewing a manhole chimney utilizes a circumferentially stretchable liner sleeve which is inserted into the manhole and pressed by an inflatable bladder into engagement with the walls of the manhole chimney. The sleeve is coated with an uncured resin, which is allowed to cure as the sleeve is pressed against the chimney walls, thereby attaching the sleeve to the walls of the manhole chimney. The stretchable sleeve eliminates air spaces between the sleeve and the chimney walls, and precludes formation of undesirable folds in the sleeve. The sleeve stretches circumferentially up to 150% of its unstretched diameter, while having a substantially unstretchable length.

BACKGROUND OF THE INVENTION

Conventional manholes include a lower or bottom pan, a barrel having aconstant diameter adjacent the pan, a concentric or eccentric coneextending upwardly from the barrel, one or more adjusting rings toadjust the overall height of the manhole, and a casting frame on top ofthe adjusting rings to support a lid at an elevation substantially levelwith the surrounding pavement. The casting frame is preferably sealed tothe uppermost adjusting ring to preclude or minimize water flow into themanhole. The cone and adjusting rings are commonly known as the manholechimney. Most manhole structures are unique in size and shape, withvarying diameters and depths.

The upper portion of the manhole is normally the weakest portion of thestructure, due to traffic loading, freeze and thaw, impact from snowplows, and deteriorated small pieces of construction materials used tomake the final grade adjustment for the surrounding road. Sub-standardconstruction methods can also lead to damage or deterioration of theupper manhole structure. Thus, the manhole chimney is vulnerable toallowing surface water and subsidence of soil to enter the manhole,which eventually leads to a structural failure of the manhole.

One method of repairing manholes involves cured-in place liners orsleeves. Due to the dimensional differences in manholes, these prior artrepair liners are custom tailored for each specific manhole structure,which necessitates personal measurements for each manhole. Often times,the person must enter the manhole to measure difficult shapedstructures. Such customization inherently increases costs for theone-of-a-kind liners.

The prior art liners generally are constructed of materials such asfiberglass or needle-punched felt material and PVC. These materialsoffer little or no stretching, particularly circumferentially. Due tothe lack of stretchability in these prior art liner sleeves, it iscritical that the manhole measurements be precise, which is nearlyimpossible. When measurements are not precise, the liner sleeve may betoo small or too large. When the sleeve is too small, an annular spaceis created between the liner and the manhole structure, which allowssurface water or ground water to migrate and enter the manhole, whichsubsequently enters the water collection system. When the liner is toolarge, a fold is created in the liner, which produces a rough innersurface, which reduces capacity for a person entering the manhole formaintenance and provides an area upon which obstacles may snag or catch.For example, if a bladder is used to expand the liner outwardly intoengagement with the manhole walls, the bladder often becomes caught onthe folds, which complicates removal of the bladder.

Therefore, a primary objective of the present invention is the provisionof an improved method for repairing a manhole using a stretchable linersleeve.

Another objective of the present invention is the provision of auniversal liner that can be used to repair and renew manholes havingvarious sizes.

A further objective of the present invention is the provision of aone-size fabric liner which stretches circumferentially to variousdiameters up to 150% of the unstretched diameter for use in manholes ofvarying sizes and shapes.

Another objective of the present invention is the provision of a methodof repairing a manhole chimney by inserting a resin-impregnated sleeveinto the chimney and stretching the sleeve circumferentially intoengagement with the chimney, and then allowing the resin to cure inplace so as to bond the sleeve to the chimney.

Another objective of the present invention is the provision of a methodfor repairing a manhole chimney using a sleeve which is inserted intothe chimney and pressed into contact with the chimney, with theinsertion and pressing steps being sequential or simultaneous.

A further objective of the present invention is the method of repairinga manhole chimney using a resin-coated sleeve which eliminates spacebetween the sleeve and the chimney and which precludes folds in thesleeve after the sleeve is attached to the chimney.

Still another objective of the present invention is the provision of astretchable liner for repairing manhole chimneys which is economical tomanufacture, easy to install, and durable in use.

These and other objections will become apparent from the followingdescription of the invention.

BRIEF SUMMARY OF THE INVENTION

The present invention provides a trenchless method for renewing andrepairing a chimney section of a manhole, so as to eliminate surfacewater and surrounding soil from entering the collection system of themanhole. The manhole chimney repair method of the present inventionutilizes a stretchable liner that conforms to changing and varying sizesin each manhole structure. The universal, one-size liner can bestretched circumferentially up to 150% of its unstretched diameter,thereby accommodating nearly all manhole chimneys. The method ofrepairing the manhole chimney using the stretchable liner eliminates theneed to measure any portion of the manhole. The stretchable nature ofthe liner assures that when the repair process is complete, no annularspaces exist between the liner and the chimney wall, and no folds existin the liner so as to provide a smooth, wrinkle-free interior surfacefor the chimney. The liner sleeve is stretched using fluid pressureacting directly on the interior of the sleeve or through an inflatablebladder inserted into the sleeve.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a manhole having an eccentric cone,before the repair process of the present invention takes place.

FIG. 2 is a sectional view of the liner sleeve of the present inventionready for impregnation of a thermal-set resin into the fabric fibers ofthe sleeve using a vacuum process.

FIG. 3 is a schematic view showing the vacuum impregnation process forthe resin.

FIG. 4 is a view showing the resin-impregnated liner sleeve.

FIG. 5 is a view showing the sleeve being inverted such that theresin-coated fibers are reversed from the interior of the sleeve to theexterior of the sleeve.

FIG. 6 is a view showing the first step of the manhole chimney repairmethod according to the present invention wherein the sleeve is insertedinto the chimney.

FIG. 7 is a view showing the second step of the chimney repair method ofthe present invention using a pipe with an inflatable bladder insertedthrough the sleeve to stretch the sleeve into contact with the wall ofthe chimney.

FIGS. 8 and 9 are views showing an alternative method of stretching theliner using an inflatable bladder.

FIGS. 10 and 11 are views showing an alternative process for insertingand stretching the liner sleeve for repair of a manhole chimney.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 shows a cross-sectional view of a manhole 10. The manhole 10includes a bottom pad 12, a barrel 14 above the bottom pad 12, a cone 16supported by the barrel 14, and a plurality of adjusting rings 18supported by the cone 16. A casting frame 20 resides upon the upper mostring 18 and supports a lid 22. The casting 20 is normally sealed to thetop ring 18. It is understood that one or more rings 18 may be used toadjust the height of the manhole 10 such that the lid 22 issubstantially at the level of the pavement 24 surrounding the manhole10. Also, while FIG. 1 shows the cone to have an eccentric shape, it isunderstood that a concentric cone can be utilized such that the manhole10 has a symmetrical cross-sectional appearance. FIG. 1 also shows anoptional pipe invert 26 in the bottom pad 12. While each manholegenerally has unique size and shape, it is generally understood that thebasic construction of the manhole 10 is similar in all manholes. Thecone 16 and rings 18 generally define the chimney of the manhole 10.

The present invention is directed towards a method of repairing andrenewing the manhole chimney using a stretchable liner. The liner isformed by a tubular sleeve 28 including a fabric fiber material 30 whichcan be stretched circumferentially up to 150% of its non-stretcheddiameter. The sleeve 28 has substantially no longitudinal stretchingcharacteristics along its length. A preferred fabric for the sleeve 28is a material known as “stitch bond” distributed by LMK Enterprises,Inc. of 1779 Chessie Lane, Ottawa, Ill. 61350. The fabric is preferablycoated on one side with an impermeable polymer film 32 such aspolyurethane, PVC, or similar coatings having an elastic characteristic.The sleeve 28 is constructed to a generic size or diameter thataccommodates most manhole chimneys. The sleeve 28 may have a significantlength which can be cut to the appropriate length at the manhole site.

The sleeve 28 is impregnated with a resin, preferably a thermal-setresin, which is forced into the fabric fibers. A method of impregnatingthe sleeve 28 with the resin is shown in FIGS. 2-5. More particularly,as originally formed, the fabric fibers 30 of the sleeve 28 are on theinside of the sleeve, while the film coating 32 is on the exterior ofthe sleeve 28. One end of the sleeve 28 is connected to a vacuum bag 36using tape or other adhesive 38. The opposite end of the vacuum bag 36is connected to a vacuum hose 40 through a threaded coupling 42. Thevacuum hose is connected to a vacuum source 44, as seen in FIGS. 2 and3. A wick 46 extends through the length of the vacuum bag 36 andfunctions to expel air from the sleeve 28 during the resin impregnationprocess.

As seen in FIG. 3, a slug 48 of resin is introduced into the open end ofthe sleeve 28 and is forced through the sleeve 28 so as to impregnatethe fabric fibers 30. A pipe 50 may be rolled over the sleeve 28 so asto push the slug 48 through the sleeve 28. Simultaneously oralternatively, the vacuum source 44 can be actuated to pull the resinslug 48 through the sleeve 28, thereby coating and impregnating thefabric fibers 30 with the resin material.

After this internal impregnation process is completed, the sleeve 28 isin the form of a flattened tube, as shown in FIG. 4, with the filmcoating 32 on the outside and the resin coated fibers 30 on the inside.The sleeve 28 is then inverted, as shown in FIG. 5, so that theresin-coated fibers 30 are on the outside and the film coating 32 is onthe inside, as shown in FIG. 5.

As an alternative to the vacuum impregnation process, the sleeve 28 canbegin with the fabric fibers 30 on the exterior, and the resin poured onthe fibers 30 then pressed into the fibers 30 by a person or by othermeans. This manual impregnation eliminates the inversion step for thesleeve 28 since the resin is applied to the exterior of the sleeve.

FIGS. 6 and 7 show a first method of repairing the manhole chimneyaccording to the present invention. Upon arriving at the site, thesleeve 28 is cut to length, and then inverted, as described above. Themanhole lid 22 is removed, and a retaining or support ring 52 is set onthe pavement 24 around the opening of the manhole 10. The sleeve 28 isinserted into the manhole 10, with the upper end of the sleeve 28 beingwrapped over the support ring 52 so as to retain the sleeve 28 inposition. Then, as seen in FIG. 7, a large pipe 54 having a lengthgreater than the height of the manhole chimney and a diameter smallerthan the diameter of the casting frame 20 is lowered into the manhole 10through the sleeve 28. The upper end of the pipe 54 includes a radiallyextending flange 56 to support the pipe on the support ring 52. As shownin FIG. 7, a camera 60 may be lowered through the pipe 54 to verify theposition of the sleeve 28 and the pipe 54 within the manhole 10.

An inflatable bladder 58 extends around the perimeter of the pipe 54 andalong its length. The bladder 58 is deflated when the pipe 54 is loweredinto the manhole 10. After the pipe 54 and bladder 58 are in position,the bladder 58 is inflated with air or a liquid under pressure, from aconvenient fluid source (not shown). As the bladder 58 inflates, thesleeve 28 is stretched circumferentially and pressed into engagementwith the internal chimney wall of the manhole 10 as shown in FIG. 7. Theuncured resin adheres the sleeve 28 to the cone 16 and adjustment rings18. Upon curing of the resin, the sleeve 18 is bonded and mechanicallyadhered to the inner wall of the manhole chimney. The expansion of thebladder 28 assures that no annular spaces reside between the sleeve 28and the chimney wall. Also, the stretching of the sleeve 28 from afirst, unstretched diameter to enlarged diameters matching the contourof the chimney precludes undesirable folds in the sleeve 28. After thesleeve 28 has been stretched into contact with the chimney walls, thebladder 58 can be deflated, and then removed with the pipe 54 from themanhole 10. The resin may be allowed to cure with the bladder 58inflated in the manhole 10. Alternatively, the pipe 54 and bladder 58may be removed from the manhole before the resin is fully cured.

A second method of repairing the manhole 10 according to the presentinvention is shown in FIGS. 8 and 9. In this alternative repair process,the pipe 54 and bladder 58 is replaced with an inverted bladder 62. Oneend of the bladder 62 has an air inlet 64, while the opposite end of thebladder 62 includes a control rope or cord 66. A hose barb 68 isprovided between the opposite ends of the bladder 62.

After the sleeve 28 is inserted into the manhole 10, as described abovewith respect to FIGS. 6 and 7, the deflated bladder 62 is positionedadjacent the top of the manhole 10, and then inflated such that theinverted portion of the bladder 62 is forced downwardly into the manhole10. As inflation of the bladder 62 continues, the sleeve 28 is stretchedcircumferentially and pressed into engagement with the chimney walls, asdescribed above. The bladder 62 can remain inflated while the resincures, or can be deflated and removed from the manhole 10, before theresin cures. The rope 66 is used to pull the bladder 62 out of themanhole 10 after the bladder 62 is deflated.

A third method of repairing the manhole 10 according to the presentinvention is shown in FIGS. 10 and 11. In this method, the sleeve 28 isinverted within the bladder 62. As the bladder 62 is inflated, both thesleeve 28 and the bladder 62 are forced downwardly into the manhole 10and into engagement with the walls of the chimney. As the fluid or airpressure in the bladder 62 unfolds the inverted sleeve 28 from theposition shown in FIG. 10 to the position shown in FIG. 11, the sleeve28 rolls down into engagement with the chimney walls and is pressedagainst the walls by the pressure in the bladder 62.

The bladders 58, 62 preferably are made of a material that stretches upto 100% so as to conform to the various dimensions of the manholechimney. A preferred bladder material is a gum rubber product made byAmerican Logi Ball of Canada or by American Elastomer Products ofHouston, Tex.

The invention has been shown and described above with the preferredembodiments, and it is understood that many modifications,substitutions, and additions may be made which are within the intendedspirit and scope of the invention. From the foregoing, it can be seenthat the present invention accomplishes at least all of its statedobjectives.

1. A universal manhole liner for repairing manholes having differentdimensions from one another and each manhole having varying diametersalong its height, comprising: a tubular fabric sleeve impregnated withresin having a constant unstretched diameter along its length; and thefabric being capable of stretching circumferentially to varyingdiameters for contact with the manhole along the varying diameters. 2.The liner of claim 1 wherein the resin is vacuum impregnated into thefabric.
 3. The liner of claim 2 wherein the sleeve is connected at afirst end to a vacuum bag, and the resin is inserted into the sleeve ata second end, and wherein a wick extends through the bag into the liner,such that when a vacuum is applied to the bag, air is drawn from thesleeve and the resin is pulled through the sleeve.
 4. The liner of claim1 wherein the resin is poured onto the fabric and manually pressed intothe fabric.
 5. The liner of claim 2 having a non-stretched diameter andbeing stretchable to a diameter 150% greater than the non-stretcheddiameter.
 6. A manhole liner for repairing a manhole having varyingdiameters along its height, the manhole liner comprising: a resinimpregnable tubular fabric sleeve having a constant unstretched diameteralong it length; wherein the fabric sleeve being capable of stretchingcircumferentially to varying diameters for contacting with the manholealong the varying diameters while the length of the sleeve does notdecrease.
 7. The liner of claim 1 wherein the unstretched diameter ofthe sleeve is smaller than the smallest of the varying diameters of themanhole.
 8. A method of repairing a manhole having varying diametersalong its height, comprising: taking a tubular fabric sleeve having aconstant unstretched diameter along its length with the fabric beingcapable of stretching circumferentially for contact with the manholealong the varying diameters; applying a resin to the sleeve, the resinbeing uncured and unhardened; positioning the sleeve in the manhole;inserting an inflatable bladder into the sleeve; inflating the bladderto stretch the sleeve circumferentially into contact with the manholealong its varying diameters; allowing the resin to cure and harden so asto attach the sleeve to the manhole; and removing the bladder from themanhole.
 9. The method of claim 8 wherein the bladder is inflated byapplying fluid pressure within the bladder.
 10. The method of claim 8wherein the sleeve stretches up to 150% of its unstretched diameter. 11.The method of claim 8 further comprising maintaining a first end of thesleeve outside the manhole.
 12. The method of claim 8 further comprisinglowering a camera through the sleeve to view the sleeve contacting themanhole at the varying diameters.
 13. The method of claim 8 wherein thesleeve is inserted into the manhole by inverting the sleeve.
 14. Themethod of claim 13 wherein the sleeve is stretched and invertedsimultaneously so as to engage the manhole during insertion.
 15. Themethod of claim 8 wherein the unstretched diameter of the sleeve issmaller than the smallest of the varying diameters of the manhole. 16.The method of claim 8 wherein the sleeve bonds to the manhole.
 17. Themethod of claim 8 wherein the step of applying the resin to the sleevecomprises vacuum impregnating the sleeve with the resin.
 18. The methodof claim 17 wherein the vacuum impregnation uses a vacuum bag attachedto a first end of the sleeve and the resin is introduced into the sleeveat a second end opposite the first end, and a vacuum is applied to thebag to draw the resin through the sleeve.
 19. The method of claim 18further comprising providing a wick through the vacuum bag and into thesleeve through which air is drawn by the vacuum.